M4 TP Call Limit

In rare cases Termination Point's Call Limit can be ignored, e.g. TP could send more calls compared to Call Limit setting.

Why it can happen - explanation follows:

When call is placed, radius generates routing list and sends it to the switch. Let's say routing list tells to route the call over Termination Points (TP) A B and C.

If TP C has call limit 1 we can have situation when over the same time C can have more than 1 call at the same time, because the check when the call is initiated and when TP is reached is not instant.

Imagine C has 0 calls currently.

1. Call #1 is placed and routing table A B C is sent to the switch, because C has 0 calls.

2. Call #2 is placed and routing table A B C is sent to the switch, because C has 0 calls.

3. Call #1 tries to place call over A and B and fails, C succeeds.

4. Call #2 tries to place call over A and B and fails, C succeeds.

There is a delay between 2 and 3 that is why C can pass 2 calls.

There is no check right before trying to call over C because switch cannot check it at this moment.

That is why call limit can be ignored at some rare cases.

As this is Class 4 switch, this should be not important.